Colour Coding
by emopoet28
Summary: It was a mystery the likes of which John Watson had never yet faced – figuring out Sherlock's eye colour. What the bloody hell is it?


Author's note: Do I really want this for a title? Idk. I forgot I had written this fic. I was bored one day and I decided to write a one shot based on whatever song comes up next on my iTunes shuffle. I decided I'd finish it today, so here it is. Hope you guys like it. Leave me a review?

* * *

><p>It was a mystery the likes of which John Watson had never yet faced – figuring out Sherlock's eye colour. W<em>hat the bloody hell is it? <em>It was enough to drive him mad. He was a man immersed in medical science after all. He knew of Gregor Mendel and the principle of genetics. Eye colour was determined by three genes and it certainly did not change drastically from one moment to the next. At least not _normally_. Of course it had to be the world's _only_ consulting detective who would defy the very laws of Mendelian inheritance. It could only be _Sherlock Holmes._

Green. Blue. Gray. A whole spectrum of light and shadow. Each colour would melt and bleed into the next, always changing and always transforming. When John would reach the conclusion that Sherlock's eyes were without a doubt green, he'd find himself looking in his flatmate's direction once more, only to realize his eyes were a light shade of blue. It was frustrating and infuriating and _oh so_ captivating. John couldn't deny his excitement at witnessing all the possible blends and mixtures of pigments and photons, as Sherlock would be when faced with a case involving a sealed room within another sealed room and a triple homicide.

He'd often find himself staring for seconds, even minutes at a time, just waiting and anticipating the transitions between green and blue, between blue and gray. When he would grow aware that he appeared to be ogling Sherlock, he would lick his lips and turn away before the pink flush settled on his cheeks. It was downright maddening and almost embarrassing to be so fixated on another man's eyes. Sometimes, he would be so immersed in his observation that he'd lose track of the conversation.

"The painting's a fake," Sherlock deduced from the corpse of a security guard that had washed up on the south bank of the Thames. Sherlock had laid it all out, enjoying the attention of his captive audience. John, however, was too busy staring fixedly at the changing colours of Sherlock's eyes to focus on the analysis. Watching the transformation of iris pigments from blue to green then to blue again, he had found it remarkably fantastic. And much to his own surprise, the word _fantastic_ had just escaped from his mouth. It was just John's luck that his outburst fit well within the context of the situation – a simple complement for Sherlock's brilliant powers of deduction. John did it almost too often now so the praise would not be out of place, however it did have the consequence of boosting Sherlock's already enormous ego, no matter how well-deserved the praise may be.

John could not for the life of him understand how his brain function could fluctuate from processing the information from his ears as he listened to Sherlock to contemplating the secret that teased him from within those almond-shaped eyes. He knew it was dangerous to lose focus. He had learned that lesson in Afghanistan; he had learned it as he lived it. And Sherlock was perhaps just as dangerous as the battlefield. Maybe more.

As a medical man, John devoted a huge amount of effort to his case study. The scientific method was a surefire way to get an answer. _Wasn't it?_ Over time, he had started noticing a pattern.

_Blue._ Sherlock's eyes had a blue tinge about them when they were on a case. The shades would vary depending on the rating. The more exciting the case, like a seven or an eight, the brighter the blue. John had attributed it to Sherlock's work. Pupils were known to dilate during certain cognitive processes, and with the amount of deducing Sherlock does, it was no surprise. Dilated pupils let in more light, which was the reason why the colours would appear differently. But pupils would also dilate in extremely emotional situations – fear, pain, even attraction. Other times, narcotics. John knew he had to watch out for the latter. Blue could be a sign of either good or bad things. John knew he had to be prepared.

_Gray._ His eyes were often gray when he was with Mycroft or Lestrade. Always though with Anderson. John associated the colour with a perceptible mischievous or maybe even rebellious streak. His eyes would turn a steely gray when he was doing his best to be bloody difficult. This often happened when Sherlock was bored, and John had to suffer for it. John didn't like the colour all that much, but he couldn't deny how beautiful those storm eyes looked on Sherlock. Set on his face, among those high cheek bones and the gentle slope of his nose, he looked positively regal and elegant. That is to say, before the sharp wit released a few well-composed insults at all his usual targets.

John concluded that Sherlock's default eye colour was green, although John rarely saw it. He only caught glimpses of it, when they finish a case or when Mycroft leaves the flat. It almost seemed like a response of relief, like letting out a breath of air Sherlock didn't even knew he was holding. It was John's favourite colour for Sherlock's eyes, because it meant he was relaxed and that doesn't happen as often as John would have wanted. It was the colour of contentment. He collected those moments when he does manage to see the elusive green. When they're having dinner at Angelo's. When they're drinking tea together while watching crap telly. When John would walk through the door with the groceries. _No. That was just a trick of the light. _

John refused to entertain the thought. He would rather not think about it lest it showed on his face. Lest Sherlock could read it on his face. He didn't allow himself to even consider the possibility of something more with Sherlock, even though the want for it, hidden deep inside him, grew steadily more each day.

It wasn't that he was afraid of the relationship, though he did fear something. He could only remember too well that incident at the pool when that madman Moriarty strapped explosives to his body. He could remember the streak of panic and concern in Sherlock's eyes. His eyes were never a brighter blue than he had seen back then. John could tell Sherlock's sympathetic nervous system was in overdrive – fight or flight. Aftershocks of the surprise still hit him from time to time, when he remembered how Sherlock hadn't run despite John telling him to. John knew for certain then, despite Sherlock's mantra of '_Caring won't help save them so I will continue to not make that mistake_', that he cared very much. Sherlock cared for John. So no, John did not fear a relationship with this man; he did not fear rejection. He had enough confidence, as much as three continents could offer, after all. No, his fear had something to do with that night at the pool. The way John was used as a leverage, as a way to control Sherlock Holmes. John was Sherlock's kryptonite. Caring for John made Sherlock vulnerable and almost irrational. _Why didn't he run? He should have. He should have saved himself._ If being flatmates, if being friends could cause this much harm and this much damage to a great man like Sherlock Holmes, what more… John didn't even want to finish the thought. People like John were a dime a dozen; he was very much ordinary. But the world _needs_ Sherlock Holmes. John couldn't gamble on Sherlock's life. He wouldn't.

But something happened while Sherlock was on a case. He went off on his own again and John was frantic with worry. He had no form of protection at all, as far as John could tell. _The bloody idiot. He should have at least taken my pistol._ John ran down side streets and back alleys, trying to find that familiar silhouette. He kept running until he had heard the sounds of bins being turned over, scuffling and then a shout of pain. John ran as fast as he could, while thinking of how much more his heart could beat at this rate before it spontaneously exploded within his thoracic cavity. He prayed it didn't give out before he had reached Sherlock. He saw two dark shapes in the alley. One was slumped on the ground; the other was standing with a knife in his hand. His eyes adjusted enough to the dark to know that the one standing wasn't Sherlock. John dived for the man. Caught off guard, the man didn't react fast enough. The impact John made on his body sent them hurtling toward the ground. John quickly positioned his arms around the man's neck, using the stronghold he had learned in the army which could render a man unconscious within half a minute. As soon as he had finished with him, John rushed to the Sherlock's slumped form. He was breathing. _Thank God._ But there was a gash on his left side and blood was pouring out.

"He swiped at me, and I jumped a second too late," Sherlock explained.

John handed Sherlock his phone so he could call for an ambulance and busily set about to stop the bleeding. When the bleeding ceased to be life-threatening, John allowed himself to finally look at the detective since coming into the alley. His face was paler than he had ever seen it. His hair was sticking to his forehead and his face was drenched in sweat. The breath came out of his mouth in shallow bursts. John knew Sherlock's system was flooded with adrenaline right now and could very well go into shock. But he was quite puzzled by what he saw in Sherlock's eyes. Based on John's study, they should be a clear blue. _Not green. How can he be relaxed when he's just been stabbed?_ Sherlock saw the look on John's face and managed to move his lips to form the words, "What's wrong?"

Before John could answer, he heard the sound of footsteps. Lestrade had arrived, along with an ambulance and a few other officers.

"Quickly, get him to the hospital," John had said. And they had wasted no time.

Sherlock was released after a couple of days. It would have been sooner had he not ripped his stitches. Sometimes John couldn't understand how this genius, _his_ genius, his _Sherlock_, could be such an idiot.

They were in the living room, Sherlock lying down on the couch, a compromise John had agreed to even though mandatory _bed_ rest did actually specify a place, while he sat with his back to him, typing up Sherlock's last case. It was Sherlock who brought it up.

"John, something still bothers me."

John turned in his seat to look at his friend. His instinct told him to check the bandages for any sign of bleeding, to check if Sherlock's in any pain. But the puzzled expression on Sherlock's face told him this was about something else entirely.

"What is it?" He asked, not being able to deduce the topic of conversation from Sherlock's eyebrow or the curve of his lip or some other seemingly insignificant detail from which Sherlock could glean someone's life story.

"The other night when I was stabbed, you didn't answer my question."

Sherlock's words had stirred the memory within and John knew exactly what his friend was referring to. The absolutely inappropriate green of Sherlock's eyes. John cleared his throat and tried feigning ignorance. He was a bit embarrassed. Answering the question entailed revealing his whole study of Sherlock's eye colour and he wasn't sure he wanted Sherlock to know of it.

John need not have bothered with the act, because Sherlock being, _well_, Sherlock could see through it easily.

"Tell me, John, please. The fact that I could not and have not been able to deduce it is driving me insane."

Sherlock looked at him with those pleading, puppy dog, light blue eyes. And John found himself shaking his head, mostly in amusement, at how Sherlock could always have his way with him. At how willingly he allowed himself to be subjected to Sherlock's whims and flights of fancy. At how easily he said yes to him. The thought didn't alarm him at all even though the soldier in him knew it should.

He breathed a sigh in resignation and said, "You're going to think I'm mad. You see, I've been conducting an experiment of my own. Well, okay, not really. It's actually a case study."

"A case study about what?"

"About you. Obviously."

Sherlock smiled at John's use of the word and said, "About me?"

"Specifically, your eyes and how they change colours. I've been trying to establish a correlation between the hues and shades of colour and your general moods."

Sherlock sat up, elbows on his knees, tenting his fingers before his lips in a pose that John could only have interpreted as _"Fascinating. Tell me more."_

And so he did. John tried to make himself appear to be less obsessed than he was, but the words were out of his mouth before he could even think them through properly. He was laying it all out, the parameters of his study, the different facets of Sherlock's moods and then the pattern of colours. The glorious, extraordinary and drive-you-crazy colours.

"The other night, when you were possibly bleeding to death, it surprised me to see that your eyes were green. They should have been blue, but there wasn't even a tinge. Basically, it seems as though my study has been invalidated."

The look of concentration on Sherlock's face compelled John to stand up and move to sit beside his friend. He was as still as a statue. But his eyes told a different story. The colours were dancing in Sherlock irises. They honestly were. And John was absolutely enthralled and content just sitting there and witnessing it all.

A few minutes passed and Sherlock finally turned to look at him, as if registering for the first time that John had moved from where he sat before.

"I think I've figured it out."

"You what?"

"The mystery, John. _Green._ Don't you see? I was bleeding out but I wasn't scared. I've never been one to be afraid, certainly not of dying. But I was relaxed because _you_ were there."

A sense of tightness materialized in John's chest and he tried to swallow it down but it wouldn't go away. He had a feeling that this was heading into dangerous territory, but he couldn't bring himself to speak.

Sherlock was closing the distance between them. Leaning in closer and closer until their faces were separated by mere inches. John hazarded a glance at Sherlock's full lips. He wondered what they would feel like upon his own. He wondered what Sherlock would taste like. His mind was assaulted by a myriad of similar thoughts which basically directed blood to the lower region of his anatomy. John tore his eyes away from Sherlock's lips and met his gaze. He admired his self-restraint. He wanted nothing more than to make those last few inches disappear. Nothing more than to kiss Sherlock senseless. Nothing more than to have him, all of him. There. On the couch. Or the floor. The logistics didn't matter.

The soldier in him was fighting off the surge of hormones within him and John tried to ignore the fact that his jeans seemed to be tighter. _Control yourself._

Sherlock didn't blink. At first his eyes were green, but John could already anticipate the change that was going to occur. He could read the patterns and recognize the swirl and mixture and swell of those colours. John's mouth opened in amazement. Blue. Brighter and fuller than he had ever seen it.

"John, I pride myself in noticing the little things. The details and hints that most people would just disregard or ignore. They never observe, never notice. And now, I know how that feels. All this time… staring at me in the face and I didn't see it. Didn't realize when it was so painfully obvious."

John had never seen those colours so still and steady before. They had always been so volatile, so dynamic, much like how Sherlock was. Always in constant motion. Always after the next mystery.

"What are my eyes telling you, John?"

"They're telling me I should _fucking_ kiss you right now. _Fuck._"

Sherlock grinned and close his eyes in anticipation.

"But Sherlock… won't this change everything? All those criminals, Moriarty even… if people find out, they'll use me to get to you. I'd put you in danger. I'd be a… liability."

Sherlock merely raised one of his eyebrows in response in a look that clearly said, _"John, you're being an idiot again."_

"Could be dangerous. But when has that ever stopped us?" Sherlock looked at him and fixed him with his still blue eyes.

It was all John needed to push him to close the gap between them, his lips on Sherlock's.

The want burst from him. The waves of emotion he hadn't allowed himself to feel came at him from everywhere and he was drowning and it was bloody amazing.

_This_, John thought. This must be how Sherlock feels every single time he deduces and solves the puzzles. The mysteries. Every single time they successfully close a case. And John soared at the realization that he too had solved a mystery. The mystery of Sherlock's eye colour. God, he needed a better title, he thought to himself as he smiled into the kiss, his hand running through the dark curls of Sherlock's hair and the other around his waist to bring him closer. Case closed.


End file.
